Feedback on Desalination

Last week, after posting the newest blog here on CCF, I immediately received a response from Peter Gleick, one of the authors of the report about water desalination that I had discussed.  Through my twitter account, he led me to the Pacific Institute’s more recent publications.

  Peter Gleick@PeterGleick 12 Nov

@MichaTomkiewicz Thanks, but you might also look at our updated analyses! …. And this one: …

Well – when Peter Gleick tweets, I listen. Here are some excerpts of both links, taken directly from the documents:

Key Issues in Seawater Desalination in California: Energy and Greenhouse Gas Emissions

Published: May 1, 2013
Authors: Heather Cooley, Matthew Heberger
Pages: 37

Interest in seawater desalination in California is high, with 17 plants proposed along the California coast and two in Mexico. But removing the salt from seawater is an energy-intensive process that consumes more energy per gallon than most other water supply and treatment options. A new report from the Pacific Institute series “Key Issues for Seawater Desalination in California” describes the energy requirements and associated greenhouse gas emissions for desalinated water and evaluates the impact of short- and long-term energy price variability on the cost of desalinated water.

Energy requirements are key factors that will impact the extent and success of desalination in California. “Key Issues for Seawater Desalination in California: Energy and Greenhouse Gas Emissions” shows energy requirements for seawater desalination average about 15,000 kWh per million gallons of water produced. By comparison, the least energy-intensive options of local sources of groundwater and surface water require 0 – 3,400 kWh per million gallons; wastewater reuse, depending on treatment levels, may require from 1,000 – 8,300 kWh per million gallons; and energy requirements for importing water through the State Water Project to Southern California range from 7,900 – 14,000 kWh per million gallons.

“Beyond the electricity required for the desalination facility itself, producing any new source of water, including through desalination, increases the amount of energy required to deliver and use the water produced as well as collect, treat, and dispose of the wastewater generated,” said Heather Cooley, co-director of the Pacific Institute Water Program and report author. Conservation and efficiency, by contrast, can help meet the anticipated needs associated with growth while maintaining or even reducing total energy use and greenhouse gas emissions.”

Desalination is a reliable source of water, which can be especially valuable during a drought. However, building a desalination plant may reduce a water utility’s exposure to water reliability risks at the added expense of an increase in exposure to energy price risk. Energy is the largest single variable cost for a desalination plant, varying from one-third to more than one-half the cost of produced water. Because of its high energy use, desalination creates or increases the water supplier’s exposure to energy price variability.

In California, and in other regions dependent on hydropower, electricity prices tend to rise during droughts, when runoff, and thus power production, is constrained and electricity demands are high. Additionally, electricity prices in California are projected to rise by nearly 27% between 2008 and 2020 (in inflation-adjusted dollars) to maintain and replace aging transmission and distribution infrastructure, install advanced metering infrastructure, comply with once-through cooling regulations, meet new demand growth , and increase renewable energy production. While rising electricity prices will affect the price of all water sources, they will have a greater impact on those that are the most energy intensive, like desalination.

The high energy requirements of seawater desalination also raise concerns about greenhouse gas emissions. In 2006, California lawmakers passed the Global Warming Solutions Act, or Assembly Bill 32, which requires the state to reduce greenhouse gas emissions to 1990 levels by 2020. Thus, the state has committed itself to a program of steadily reducing its greenhouse gas emissions in both the short- and long-term, which includes cutting current emissions and preventing future emissions associated with growth.  Desalination ­­– through increased energy use – can cause an increase in greenhouse gas emissions, further contributing to the root cause of climate change and running counter to the state’s greenhouse gas reduction goals.

There are several ways to reduce the greenhouse gas emissions associated with desalination plants, including (1) reducing the total energy requirements of the plant; (2) powering the desalination plant with renewable energy; and (3) purchasing carbon offsets.

“Even renewables have a social, economic, and environmental cost, albeit much less than conventional fossil fuels. Furthermore, these renewables could be used to reduce existing emissions, rather than offset new emissions and maintain current greenhouse gas levels. Offsets also raise concerns; caution is required when purchasing offsets, particularly on the voluntary market, to ensure that they are effective, meaningful, and do no harm,” said Cooley. “Energy use is not the only factor that should be used to guide decision making. However, given the increased understanding of the risks of climate change for our water resources, the importance of evaluating and mitigating energy use and greenhouse gas emissions are likely to grow.”

The “Key Issues for Seawater Desalination” series is an update to the 2006 Pacific Institute report, “Desalination with a Grain of Salt,” which has proven to be an important tool used by policy makers, regulatory agencies, local communities, and environmental groups to raise and address problems with specific proposals, downloaded nearly 700,000 times. Researchers conducted some 25 one-on-one interviews with industry experts, environmental and community groups, and staff of water agencies and regulatory agencies to identify some of the key outstanding issues for seawater desalination projects in California. The resulting reports address proposed desalination plants in Californiacosts and financing, and energy and greenhouse gas emissions, with a forthcoming report on marine life and coastal ecosystem impacts.

Key Issues in Seawater Desalination in California: Costs and Financing

Published: November 27, 2012
Authors: Heather Cooley, Newsha Ajami
Pages: 48

Economics – including both the cost of the water produced and the complex financial arrangements needed to develop a project – are key factors that will determine the ultimate success and extent of desalination in California. New research from the Pacific Institute, “Key Issues for Seawater Desalination in California: Cost and Financing,” assesses desalination costs, financing, and risks associated with desalination projects. The Pacific Institute analysis finds that the cost to produce water from a desalination plant is high but subject to significant variability, with recent estimates for plants proposed in the state ranging from $1,900 to more than $3,000 per acre-foot.“Seawater desalination remains among the most expensive water-supply options available, although the public and decision-makers must exercise caution when comparing costs among different projects,” said Heather Cooley, co-director of the Pacific Institute Water Program and lead author of the report. “In some cases, costs are reported in ways that are not directly comparable. For example, some report the cost of the desalination plant alone, while others include the cost for additional infrastructure needed to integrate the desalination plant into the rest of the water system. Some estimates include costs to finance the project, while others don’t. Even when there is an apples-to-apples comparison, there are a number of site- and project-specific factors that make cost comparisons difficult, such as energy, land, and labor costs and the availability of visible and hidden subsidies.”

“Key Issues for Seawater Desalination in California: Cost and Financing” is part of a series of research reports in progress that identify key outstanding issues that must be addressed before additional proposals for new seawater desalination in California are approved. Other issues that will be addressed include the environmental impacts of seawater desalination, the cost and financing of proposed projects, and energy requirements and their greenhouse gas implications.

Our new analyses, which will be released by early 2013, seek to provide communities and decision makers with information needed to make decisions about building desalination plants and to create a more rational and sustainable policy around seawater desalination along the California coast, and elsewhere.

The debate in California is ongoing, and has recently been turning in what I consider to be a destructive direction – as a result of which, one major project has recently withdrawn its proposal.

Let’s take a look at Peter’s response. The two updates he mentions focus on energy requirements and comparative costs. By the authors’ own admission, both in the original report and in the more recent updates, costs are very soft numbers and cost comparison is a dangerous ground to walk on when analyzing the sustainability of the future. In the November 12 blog, I presented a graph taken from the 2006 report on the cost comparison between gravity surfaced water, recycled water and waste water in Los Angeles. I also mentioned there that California has a special global responsibility when treating global issues to set examples that can be expanded to a much broader use. The present difference in cost in LA between recycling waste water and water desalination is about 50%. In order to recycle water, however, you need waste water. I will expand upon the present status of global waste water in the next blog. Meanwhile, suffice it to say: more than two billion people in the world lack basic sanitation facilities. They don’t have “waste water.” Most of the water around them is “waste water.” In developed countries, where sanitation facilities are almost universal, one can recycle the water, but people have other issues with recycled water (the “yuck factor” in the September 10 blog). Almost all countries have stringent requirements about dumping waste water back into the ocean. The water needs to be treated extensively – whether it is recycled or not, so the pricing baselines for the alternative technologies are different than noted above.

For the reasons that I outlined in previous blogs, water desalination is an energy intensive business. The sources of energy that are used are important. Therefore, naturally, attempts to alleviate global fresh water stress should be closely connected to global attempts to reduce the energy reliance on fossil fuels. This can be done either directly or indirectly – through the exchange of sustainable energy with desalinated water. Such exchanges are being practiced, including one such instance in California. Advocacy for the use of renewable energy, however, shouldn’t be used as an argument against water desalination. As a long term response to water stress, there is probably no alternative to ocean desalination. Rich countries are in the position to experiment with the technology on a large scale; they have a responsibility to do so in a manner that explores sustainability and efficiency.

About climatechangefork

Micha Tomkiewicz, Ph.D., is a professor of physics in the Department of Physics, Brooklyn College, the City University of New York. He is also a professor of physics and chemistry in the School for Graduate Studies of the City University of New York. In addition, he is the founding-director of the Environmental Studies Program at Brooklyn College as well as director of the Electrochemistry Institute at that same institution.
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